20G,20#彎頭生產廠家供應商（廠家?楊春笑??話：15130812346?QQ:357197729)：

???????長半徑彎頭long?radius?elbow
異徑彎頭?reducing?elbow
帶支座彎頭?base?elbow
短半徑彎頭?short?radius?elbow
長半徑180°彎頭?long?radius?180°elbow
短半徑180°彎頭?Short?radius180°elbow
帶側向口的彎頭（右向或左向）?side?outlet?elbow?(right?hand?or?left?hand)
雙支管彎頭（?形）?double?branch?elbow
衛生級快裝彎頭Stainless?quick?elbow
不銹鋼彎頭Stainless?elbow
螺紋彎頭threaded?elbow
快裝彎頭?quick?elbow
90°彎頭?90°Elbow
承插焊彎頭?socket?welded?elbow
螺紋彎頭?threaded?elbow

曲線的曲率。平面曲線的曲率就是是針對曲線上某個點的切線方向角對弧長的轉動率，通過微分來定義，表明曲線偏離直線的程度。